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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
         // 6 - 成绩表
        // 弹出输入框邀请填写分数
        var score = prompt('请输入您的分数')
        // 使用if if。。else if。。if方法判断分数区间，并弹出
        if (score >= 90) {
            console.log('A')
        } else if (score >= 80) {
            console.log('B')
        } else if (score >= 70) {
            console.log('C')
        } else if (score >= 60) {
            console.log('D')
        } else {
            console.log('E')
        }
    </script>
</body>
</html>